Transfer of the Pectoralis Major Muscle for the Treatment of Irreparable Rupture of the Subscapularis Tendon

Background: The clinical diagnosis of a tear of the subscapularis tendon is difficult, and the resulting delays frequently cause a major time-lapse before repair is attempted. Diagnostic delay often means that surgical repair is no longer possible. In twelve patients who had an irreparable tear of the subscapularis tendon, the superior one-half to two-thirds of the tendon of the pectoralis major muscle was used as a substitute for the subscapularis tendon. In order to adapt the orientation of the transferred muscle to that of the subscapularis, it was routed behind the conjoined tendon of the coracobrachialis muscle and the short head of the biceps to the lesser tuberosity.

Methods: The operations were performed between May 1993 and June 1997. The average age of the twelve patients was sixty-five years old (range, forty-nine to eighty-one years old). Eight patients had an isolated rupture of the subscapularis tendon, and four had a concomitant lesion in the form of either a partial or a complete rupture of the supraspinatus tendon. The dominant symptoms were anterior shoulder pain and weakness that had responded poorly to nonoperative therapy. Four patients also had signs of recurrent anterior instability.

Results: After an average follow-up interval of twenty-eight months (range, twenty-four to fifty-four months), nine of the twelve patients assessed the final result as excellent or good; three, as fair; and none, as poor. Pain was reduced, with the score improving from an average of 1.7 points (of a maximum of 15 points) preoperatively to an average of 9.6 points postoperatively. The patients' subjective functional evaluation improved from an average score of 20 points preoperatively to an average of 63 points postoperatively. The average functional rating with use of the Constant and Murley score increased from 26.9 to 67.1 percent of normal. All four preoperatively unstable shoulders were stable at the time of the latest follow-up.

Conclusions: This repair technique can be recommended as a reconstructive procedure for elderly patients who have an irreparable tear of the subscapularis tendon.